1. Field of the Invention
The present invention relates to a vehicular lamp.
2. Background Art
Depending on the driving situation, a vehicular lamp (headlamp) is expected to have two light distribution patterns: a pattern in which diffused light is distributed in front of the vehicle and partially condensed light is weakened; and a pattern in which less diffused light is distributed to the front of the vehicle and localized condensed light is strengthened, such that a clear boundary appears between an irradiated portion and a non-irradiated portion. Especially in times of rain or the like, a distribution pattern with lowered illumination intensity toward a vehicle front side is effective. The difference between the two light distribution patterns lies in the intensity of the condensed light and the vertical-direction expansion of the light distribution patterns.
Many vehicular lamps that use a semiconductor light-emitting element as a light source have been developed in recent years. An LED chip used as a light source normally has a light-emitting surface with a generally oblong shape. The LED chip is disposed so as to coincide with a focus line of a reflective surface formed from a curved surface or the like whose light-emitting surface has one side end with a parabolic and cylindrical shape (see Patent Document 1 for an example).
[Patent Document 1] Japanese Patent Application Publication No. JP-A-2003-31011.
In order to realize the two light distribution patterns described above, the conventional vehicular lamps include a unit that combined a plurality of headlamps.